Association of SO 2 -Generating Pads before Packaging and during Cold Storage to Extend the Conservation of 'Italia' Table Grapes.

The SO₂-generating pads contain different concentrations of sodium metabisulfite, which absorbs water from the grapes' transpiration, releasing SO₂ gas, and there are slow-(SlowSO₂) and dual (DualSO₂)-releasing pads (fast release in the first 48 h and slow for up to 60 days). The ultra-fast SO₂-generating pad (FieldSO₂) releases the SO₂ quickly for up to 6 h, and it was designed to be used soon after the harvest and until the grapes' packaging. The goal was to study the effect of FieldSO₂ associated with SlowSO₂ and DualSO₂ pads on gray mold incidence and physicochemical and appearance characteristics of 'Italia' table grapes. Grapes were harvested from a commercial vineyard in Parana, Brazil, in 2020 and 2021, and packaged in cardboard boxes, and the treatments were as follows: control (without SO₂-generating pads); FieldSO₂ + SlowSO₂; and FieldSO₂ + DualSO₂. After 30, 45, 60, 75, and 90 days of cold storage (1 ± 1 °C), the grapes were assessed for gray mold incidence, mass loss, shattered berries, stem browning, and filamentous fungi on the surface. The use of FieldSO₂ associated with SO₂-generating pads is effective in controlling gray mold on 'Italia' table grapes, especially the treatment FieldSO₂ + DualSO₂, which provides the lowest incidence of the disease up to 90 days of cold storage, while the combination with SlowSO₂ results in intermediate efficacy. Treatments combining these SO₂-generating pads extend the postharvest shelf life of 'Italia' grapes, with few shattered berries, low mass loss and freshness of the rachis without impairing the bunch's appearance. [ABSTRACT FROM AUTHOR]